Breathing mask and mask cushion therefor

ABSTRACT

A full-face cushion ( 30 B) comprises a substantially triangularly shaped frame ( 32 ) from which extends a membrane ( 34 ). The frame ( 32 ) has a scalloped edge ( 36 ) by which the cushion ( 30 B) is affixed to a mask body ( 46 ) to form a full-face mask ( 60 B). The membrane ( 34 ) has an aperture ( 38 ) into which the wearer&#39;s nose is received. The member ( 34 ) is spaced away from the rim ( 40 ) of the frame ( 32 ), and its outer surface ( 41 ) is of substantially the same shape as the rim ( 40 ). Respective notches ( 42, 44 ) receive the bridge of the wearer&#39;s nose. The wearer&#39;s nose and lips are received through the aperture ( 38 ) into the chamber within the mask body ( 46 ). The seal forming portion ( 45 ) thus contacts both the surface of the wearer&#39;s nose and a portion of the wearer&#39;s face in the region between the bottom lip and the chin, and around the sides and over the bridge of the nose. The shape of the seal forming portion ( 45 ) is particularly suited to effectively seal the difficult region of the facial contour that is the crease between the sides of the nose and the face.

This application is a continuation of application Ser. No. 10/166,282,filed Jun. 11, 2002, now U.S. Pat. No. 6,701,927, which is acontinuation of application Ser. No. 09/316,227, filed May 21, 1999, nowU.S. Pat. No. 6,513,526, which is a continuation-in-part of applicationSer. No. 08/791,212, filed Jan. 31, 1997, now U.S. Pat. No. 6,112,746,which claims priority to Australian Application No. PO 1265, filed Jul.26, 1996, each of which is incorporated herein in its entirety byreference.

FIELD OF THE INVENTION

The invention relates generally to a full-face (ie. nose and mouth) maskand to a cushion therefor, for example, for use in the treatment ofrespiratory conditions and in assisted respiration.

BACKGROUND OF THE INVENTION

Full-face masks are commonly used in the treatment of respiratoryconditions and sleep disorders (e.g., obstructive sleep apnea) bydelivering a flow of breathable gas for, or to assist, patientrespiration. These masks typically receive a gas supply line whichdelivers gas into a chamber formed by walls of the mask. The wallsusually are semi-rigid and have a face contacting portion including anaperture which is generally aligned with the wearer's nostrils andmouth. The face contacting portion can comprise a soft, resilientelastomeric material which may conform to various facial contours. Themask normally is secured to the wearer's head by straps. The straps areadjusted to pull the mask against the face with sufficient force toachieve a gas tight seal between the mask and the wearer's face. Gas isthus delivered to the mask and through the aperture to the wearer'snasal passages and throat.

Problems often arise with masks of the above configuration. For example,the mask may be dislodged, thereby breaking the seal between the maskand wearer. This may occur if the wearer rolls over when sleepingthereby creating a drag force on the gas supply line which istransmitted to the mask, breaking the seal. In the case of a mask beingused for the administration of Continuous Positive Airway Pressure(CPAP) treatment for the condition obstructive sleep apnea, such a leakcan result in the pressure supplied to the enhance of the wearer'sairway being below the therapeutic value, and the treatment becomingineffective.

Another problem is that the face contacting portion may apply excessivepressure to the wearer's face resulting in discomfort and possibly skinirritation. This can occur because the face contacting portion has todistort beyond its normal range of elasticity to conform to certainfacial contours which requires the application of excessive forces. Insome cases these excessive pressures and forces may cause the face todistort to conform with the face contacting portion to increase wearerdiscomfort, facial soreness and ulceration.

It is an object of the invention to overcome or at least substantiallyameliorate one or more of the foregoing disadvantages.

SUMMARY OF THE INVENTION

In one broad form, the invention discloses a full-face mask cushion tosealingly connect a mask to a wearer's face, the cushion comprising:

a nasal bridge region, a cheek region and a chin region;

a first membrane comprising a substantially triangularly-shaped frame ofresilient material having a first molded inwardly curved rim;

a second membrane of resilient material, said second membrane beingthinner than said first membrane, said second membrane having a secondmolded inwardly curved rim, said second membrane curved rim spaced afirst distance from said first membrane curved rim in said cheek regionand said second membrane curved rim spaced a second distance from saidfirst membrane curved rim in said nasal bridge region, said seconddistance greater than said first distance, said distances measured whenthe mask is not in use, a portion of said second membrane curved rimforming a face contacting seal.

Preferably, the rim and seal portion are shaped to generally matchfacial contours of the facial tissue around the sides and over thebridge of the nose and between the bottom lip and the chin.

In one particularly advantageous form, the membrane is substantiallysaddle-shaped. The membrane further has a centrally located aperturethrough which the wearer's nose and mouth pass to enter said cavity.

It is preferred that the cushion and membrane each include a co-locatednotch to accommodate the bridge of the nose of the wearer. Typically,the seal portion contacts at least the wearer's nose, and preferably,also the facial tissue around the sides and over the bridge of the noseand between the bottom lip and the chin.

The invention further discloses a full-face mask for connection to awearer's face comprising:

a mask body for connection with a supply of breathable gas; and

a full-face cushion secured to said mask body, the body and cushionforming a nose and mouth-receiving cavity, said cushion including:

a nasal bridge region, a cheek region and a chin region;

a substantially triangularly-shaped first membrane of resilient materialhaving a first molded inwardly curved rim to surround wearer's nose;

a second membrane also of resilient material, said second membrane beingrelatively more flexible than said first membrane, said second membranehaving a second molded inwardly curved rim, said second molded rim beingof the same general shape as said first molded rim and fixed to andextending away from said first membrane so as to have a second membraneinner surface spaced a first distance from an outer surface of saidfirst molded rim in said cheek region and said second membrane innersurface spaced a second distance from said first membrane outer surfaceof said first molded rim in said nasal bridge region, said seconddistance greater than said first distance, said distances measured whenthe mask is not in use, a portion of said second molded rim forming aface contacting seal; and

wherein said seal portion is substantially coterminous with respect tosaid second molded rim and is resiliently deformable towards said firstmembrane in use of said mask.

The mask body can further include attachment points from which securingstraps can be attached, and by which the mask can be secured to thewearer's head. The nasal mask can yet further comprise an arm dependingfrom said body from which a further securing strap(s) can be attached.

The invention further discloses a CPAP treatment apparatus comprising:

a flow generator for the supply of gas at a pressure elevated aboveatmospheric pressure;

a gas delivery conduit coupled to said flow generator; and

a full-face mask in turn coupled to said conduit to said nasal maskincluding:

a mask body for connection with a supply of breathable gas; and

a full-face cushion secured to said mask body, the body and cushionforming a nose and mouth-receiving cavity, the cushion including:

a nasal bridge region, a cheek region and a chin region;

a substantially triangularly-shaped first membrane of resilient materialhaving a first membrane having a molded inwardly curved rim;

a second membrane having a second molded inwardly curved rim also ofresilient material, said second membrane being relatively more flexiblethan said first membrane, and being of the same general shape as saidfirst molded inwardly curved rim and fixed to and extending away fromsaid first membrane so as to have an inner surface spaced a firstdistance from said first molded rim in said cheek region and said secondmembrane inner surface spaced a second distance from said first moldedrim, said second distance greater than said first distance, saiddistances measured when the mask is not in use, a portion of said secondmolded rim forming a face contacting seal; and

wherein said seal portion is generally coterminous with respect to saidsecond molded rim and is resiliently deformable towards said firstmembrane in use of said mask.

In one particularly preferred form, a supply of gas can be provided tosaid cavity, said supply of gas assisting, but not solely causingmaintenance of a seal by said seal forming portion of said membrane tothe face of the wearer in use of the cushion.

Advantageously, because the membrane and the rim are substantiallyshaped to the facial contour, and the membrane does not need to turn inon itself, as in the prior art, thus contacting the face without foldsor creases. With the cushion/mask secured to the wearer's head, theheadstraps need only to be tensioned to balance the force due to maskgas pressure that tends to lift the mask off the face. Such relativelylower mask-to-face pressure results in greater patient comfort, and areduction in the likelihood of skin irritation.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will now be described with reference tothe accompanying drawings, in which:

FIG. 1 is a rear perspective view of a nasal mask cushion embodying thepresent invention;

FIG. 2 is a cross-sectional view of the cushion shown in FIG. 1 alongline 2—2;

FIG. 3 is a perspective view of a nasal mask including the cushion ofFIG. 1;

FIG. 4 is a perspective view of the nasal mask of FIG. 3 secured to awearer's head;

FIG. 5 is a side view of the mask cushion shown in FIG. 1;

FIG. 6 is a front view of the mask cushion shown in FIG. 1;

FIG. 7 is a rear view of the mask cushion shown in FIG. 1;

FIG. 8 is a cross sectional view of the mask shown in FIG. 1 along line8—8 of FIG. 7;

FIG. 9 is a cross sectional view of the mask shown in FIG. 1 along line9—9 of FIG. 7;

FIG. 10 is a front perspective view of a full-face mask cushionembodying the present invention;

FIG. 11 is a perspective view of a full-face mask including the cushionof FIG. 10;

FIG. 12 is an underside view of the mask cushion shown in FIG. 10;

FIG. 13 is a front view of the mask cushion shown in FIG. 10;

FIG. 14 is a rear view of the mask cushion shown in FIG. 10;

FIG. 15 is a cross sectional view of the mask cushion shown in FIG. 10along line 15—15 of FIG. 14;

FIG. 16 is a cross sectional view of the mask cushion shown in FIG. 10along line 16—16 of FIG. 14; and

FIG. 17 is a perspective view of the mask shown in FIG. 11 secured to awearer's face.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1 to 9 show a nasal cushion 30A and a nasal mask 60A embodying thepresent invention.

FIG. 1 is a perspective view of the nasal cushion 30A. FIG. 3 is aperspective view of the nasal cushion 30A attached to a mask body 46 toform the nasal mask 60A.

The nasal cushion 30A comprises a substantially triangularly shapedframe 32 from which extends a membrane 34. The frame 32 has a scallopededge 36 by which the nasal cushion 30A is affixed to the mask body 46,as presently will be described.

The membrane 34 has an aperture 38 into which the wearer's nose isreceived in use of the nasal cushion 30A. The membrane 34 is spaced awayfrom the rim 40 of the frame 32, and its outer surface 41 is ofsubstantially the same shape as the rim 40. The outer surface 41 of themembrane 34 and the rim 40 of the frame 32 also can be described asgenerally saddle shaped. The shaping of the outer surface 41 of themembrane 34 and the rim 40 of the frame 32 also include respectivenotches 42,44 that receive the bridge of the wearer's nose in use of thenasal cushion 30A.

As is best seen in FIG. 2, the frame 32 and the membrane 34 areintegrally formed, typically in a one-shot molding process. The frame 32and the membrane 34 are fabricated from a resilient material. Onesuitable such material is SILASTIC™ silicone elastomer manufactured byDow Corning. The frame 32, in a preferred embodiment, has a typicalthickness at its rim 40 of 1.5 mm. The membrane 34, in a preferredembodiment, has a typical thickness of 0.35 mm. In this way, themembrane 34 is relatively more flexible than the rim 40.

In use of the nasal cushion 30A, a wearer's nose will be inserted in theaperture 38 to engage a seal forming portion 45 (formed between thedashed lines) of the outer surface 41 to cause deformation of themembrane 34. Depending upon the securing force supplied to the membrane34, it may deform to a point where it butts against the rim 40 of theframe 32. The frame 32 has a rigidity sufficient to withstand usualsecuring pressures in use of the nasal cushion 30A to tend to retain itsshape and resist deformation. It thus acts as a supporting structure.

Referring now to FIG. 3, the nasal cushion 30A is shown attached to themask body 46 by the edge 36 of the frame 32, adhered or otherwisesecured to a flange 48 of the mask body 46. Only the outer surface 41 ofthe membrane 34 can be seen. The flange 48 includes two lower slots 50and 54 from which a first tensioning strap 68 can be attached to securethe cushion 30 and the mask body 46 (in combination) to the head of awearer.

The mask body 46 forms a cavity that can receive the nose of the wearerby the aperture 38. A port 56 is provided at the top of the mask body 46by which breathable gas can be supplied to the chamber.

Referring now to FIG. 4, a coupling tube 62 is shown above the nasalmask 60A. The coupling tube 62 is connected at one end with the inletport 56, and at the other to a socket 64 into which can be received agas delivery tube 65 for the supply of breathable gas to the chamberinternal of the mask body 46 from a flow generator 67. The mask body 46also has two vent openings 66 by which expired gas is exhausted. Thefirst fastening strap 68 is fixed between the two lower slots 50,54. Anupper slot 52 receives an arm 70, the top end of which has a resilientpad 72 to engage the forehead of the wearer. The arm 70 has two slots,only one slot 74 shown, along its side edges, by which a secondfastening strap 78 is secured.

In fitting the nasal mask 60A, the wearer's nose is received through theaperture 38 into the chamber within the mask body 46. The seal formingportion 45 thus contacts both the surface of the wearer's nose and aportion of the wearer's face in the region between the base of the noseand the upper lip, and around the sides and over the bridge of the nose.The shape of the seal forming portion 45 is particularly suited toeffectively seal the difficult region of the facial contour that is thecrease between the sides of the nose and the face. Depending upon thetension applied by the first and second fastening straps 68,78, a sealis formed with the membrane 34 remaining spaced from the rim 40 of thecushion frame 32. While the provision of pressurised gas to the ischamber of the mask body 46 assists in the maintenance of a seal betweenthe membrane 34 and the wearer's nose and face, it is not essential inmost cases, and an effective seal will be formed absent any suchpressurised gas. When relative movement of the nasal mask 60A inrelation to the wearer's head, the nose will be restrained by contactingthe frame 32. Thus only limited relative motion between the nasal mask60A and the wearer's nose and face occurs.

The membrane 34 closely imitates the facial contour, and because of itsrelatively lesser stiffness than the frame 32, can conform to particularfacial structures with minimum force, and without a tendency to fold orcrease.

If the fastening straps 68 and 78 are tensioned to excess, the membrane34 deforms to abut the rim 40 of the cushion 30A, the frame 32 thusacting as an “end limit”. In such a configuration, almost zero relativemovement can occur between the nasal mask 60A and the wearer's head.

FIGS. 10 to 17 show a full-face cushion 30B and a full-face mask 60Bembodying the present invention. Like reference numerals to those usedin describing the “nasal” embodiment of FIGS. 1 to 9 shall be used todenote like features of the “full-face” embodiment of FIGS. 10 to 17.

FIG. 10 is a perspective view of the full-face cushion 30B. FIG. 11 is aperspective view of the full-face cushion 30B attached to a mask body 46to form the full-face mask 60B.

The full-face cushion 30B comprises a substantially triangularly shapedframe 32 from which extends a membrane 34. The frame 32 has a scallopededge 36 by which the full-face cushion 30B is affixed to the mask body46, as presently will be described.

The membrane 34 has an aperture 38 into which the wearer's nose and lipsare received in use of the full-face cushion 30B. The membrane 34 isspaced away from the rim 40 of the frame 32, and its outer surface 41 isof substantially the same shape as the rim 40. The outer surface 41 ofthe membrane 34 and the rim 40 of the frame 32 also can be described asgenerally saddle shaped. The shaping of the outer surface 41 of themembrane 34 and the rim 40 of the frame 32 also include respectivenotches 42,44 that receive the bridge of the wearer's nose in use of thefull-face cushion 30B.

As is best seen in FIG. 16, the frame 32 and the membrane 34 areintegrally formed, typically by in a one-shot molding process. The frame32 and the membrane 34 are fabricated from a resilient material. Onesuitable such material is SILASTIC™ silicone elastomer manufactured byDow Corning. The frame 32, in a preferred embodiment, has a typicalthickness at its rim 40 of 1.5 mm. The membrane 34, in a preferredembodiment, has a typical thickness of 0.35 mm. In this way, themembrane 34 is relatively more flexible than the rim 40.

In use of the full-face cushion 30B, a wearer's nose and lips will beinserted in the aperture 38 to engage a seal forming portion 45 (formedinside the dashed line, see FIG. 13) of the outer surface 41 to causedeformation of the membrane 34. Depending upon the securing forcesupplied to the membrane 34, it may deform to a point where it buttsagainst the rim 40 of the frame 32. The frame 32 has a rigiditysufficient to withstand usual securing pressures in use of the full-facecushion 30B to tend to retain its shape and resist deformation. It thusacts as a supporting structure.

Referring now to FIG. 11, the full-face cushion 30B is shown attached tothe mask body 46 by the edge 36 of the frame 32, adhered or otherwisesecured to a flange 48 of the mask body 46. Only the outer surface 41 ofthe membrane 34 can be seen. The mask body 46 includes two lower slots50 and 54 and two upper slots 74 and 76 from which first and secondtensioning straps 68 and 78 can respectively be attached to secure thecushion 30B and the mask body 46 (in combination) to the head of awearer.

The mask body 46 forms a cavity that can receive the nose and lips ofthe wearer by the aperture 38. A port 56 is provided at the front of themask body 46 by which breathable gas can be supplied to the chamber.

Referring now to FIG. 17, a coupling elbow 62 is shown connected at oneend with the inlet port 56, and at the other to a socket 64 into whichcan be received a gas delivery tube 65 for the supply of breathable gasto the chamber internal of the mask body 46 from a flow generator 67.The mask body 46 also a vent opening 66 by which expired gas isexhausted. The first fastening strap 68 is fixed between to the lowertwo slots 50 and 54. The second fastening strap 78 is secured betweenthe two upper slots 74 and 76. The first and second straps 68 and 78 arejoined at each side by a bridging portion 79.

In fitting the full-face mask 60B, the wearer's nose and lips arereceived through the aperture 38 into the chamber within the mask body46. The seal forming portion 45 thus contacts both the surface of thewearer's nose and a portion of the wearer's face in the region betweenthe bottom lip and the chin, and around the sides and over the bridge ofthe nose. The shape of the seal forming portion 45 is particularlysuited to effectively seal the difficult region of the facial contourthat is the crease between the sides of the nose and the face. Dependingupon the tension applied by the first and second fastening straps 68,78, a seal is formed with the membrane 34 remaining spaced from the rim40 of the cushion frame 32. While the provision of pressurised gas tothe chamber of the mask body 46 assists in the maintenance of a sealbetween the membrane 34 and the wearer's nose and face, it is notessential in most cases, and an effective seal will be formed absent anysuch pressurised gas. When relative movement of the full-face mask 60Bin relation to the wearer's head, the nose will be restrained bycontacting the frame 32. Thus only limited relative motion between thefull-face mask 60B and the wearer's nose and face occurs.

The membrane 34 closely imitates the facial contour, and because of itsrelatively lesser stiffness than the frame 32, can conform to particularfacial structures with minimum force, and without a tendency to fold orcrease.

If the fastening straps 68 and 78 are tensioned to excess, the membrane34 deforms to abut the rim 40 of the cushion 32, the frame 32 thusacting as an “end limit”. In such a configuration, almost zero relativemovement can occur between the full-face mask 60B and the wearer's head.

The nasal cushion 30A, the nasal mask 60A, the full-face cushion 30B andthe full-face mask 60B have been described with reference to CPAP orassisted respiration treatment, however it is to be understood that theinvention generally is applicable to any application where gas and/oratomised liquid is to be supplied to the entrance of the airways. Suchapplications include nebulisers, gas masks and anaesthetic machines.

1. A mask cushion to sealingly connect a mask to a wearer's face, thecushion comprising: a nasal bridge region, a cheek region and a regionopposite the nasal bridge region; a first membrane comprising a frame ofresilient material having a first molded inwardly curved rim of saidfirst membrane; and a second membrane of resilient material, said secondmembrane being thinner and more flexible than said first membrane, saidsecond membrane having a second molded inwardly curved rim, said secondmembrane curved rim spaced a distance from said first membrane curvedrim, said distance greater than a thickness of the first molded inwardlycurved rim, said distance measured when the mask is not in use, aportion of said second membrane curved rim forming a face contactingseal structured to present a convex sealing surface with the wearer'sface, wherein: the first molded inwardly curved rim of said firstmembrane is approximately 1.5 mm thick, and the second molded inwardlycurved rim of the second membrane is approximately 0.35 mm thick.
 2. Acushion as claimed in claim 1, wherein said second molded rim and saidfirst molded rim have a co-located notch to accommodate the bridge of awearer's nose.
 3. A cushion as claimed in claim 2, wherein said firstmembrane molded rim and said second membrane molded rim aresubstantially saddle-shaped.
 4. A cushion as claimed in claim 3, whereinsaid second membrane is shaped so that said seal portion, in use,contacts at least a wearer's nose.
 5. A cushion as claimed in claim 4,wherein said seal portion, in use, contacts the facial tissue around thesides and over the bridge of the nose, and between the bottom lip andthe chin.
 6. A cushion as claimed in claim 1, wherein said second rimand seal portion are shaped to generally match facial contours in theregion of facial tissue around the sides and over the bridge of thenose, and between the bottom lip and the chin.
 7. A cushion as claimedin claim 1, wherein the first and second membranes comprise one moldedpiece, without being adhered together by an adhesive.
 8. A CPAPtreatment apparatus comprising: a flow generator for the supply of gasat a pressure elevated above atmospheric pressure; a gas deliveryconduit coupled to said flow generator; and a mask in turn coupled tosaid conduit, said mask including: a mask body for connection with asupply of breathable gas; and a cushion secured to said mask body, thebody and cushion forming a nose and mouth receiving cavity, the cushionincluding: a nasal bridge region, a cheek region and a region oppositethe nasal bridge region; a first membrane of resilient material having afirst molded inwardly curved rim; a second membrane having a secondmolded inwardly curved rim also of resilient material, said secondmembrane being relatively more flexible and longer than said firstmembrane, and being fixed to and extending away from said first membraneso as to have an inner surface spaced a distance from said first moldedrim, wherein said distance is greater than a thickness of the firstinwardly curved rim, said distance is measured when the mask is not inuse, and a portion of said second molded rim forms a face contactingseal, said second membrane fully covers the first membrane, and saidseal is generally coterminous with respect to said second molded rim andis resiliently deformable towards said first membrane in use of saidmask.
 9. The CPAP treatment apparatus as claimed in claim 8, whereinsaid mask body includes attachment points.
 10. The CPAP treatmentapparatus as claimed in claim 9, further comprising securing strapsfixed to said attachment points.
 11. The CPAP treatment apparatus asclaimed in claim 10, wherein said first and second molded rims each havea co-located notch to accommodate the bridge of a nose.
 12. The CPAPtreatment apparatus as claimed in claim 11, wherein said first andsecond molded rims are substantially saddle-shaped.
 13. The CPAPtreatment apparatus as claimed in claim 12, wherein said second membraneis shaped so that said seal portion, in use, contacts at least wearer'snose.
 14. The CPAP treatment apparatus as claimed in claim 13, whereinsaid seal portion, in use, contacts the facial tissue around the sidesand over the bridge of the nose, and between the bottom lip and thechin.
 15. The CPAP treatment apparatus as claimed in claim 8, whereinsaid second molded rim and said seal portion are shaped to generallymatch facial contours in the region of facial tissue around the sidesand over the bridge of the nose, and between the bottom lip and thechin.
 16. The CPAP treatment apparatus as claimed in claim 8, whereinthe first molded inwardly curved rim of said first membrane isapproximately 1.5 mm thick.
 17. The CPAP treatment apparatus as claimedin claim 16, wherein the second molded inwardly curved rim of the secondmembrane is approximately 0.35 mm thick.